Reserve and fill valve for self-contained underwater breathing apparatus

ABSTRACT

A fully-automatic reserve and fill valve for scuba gear, comprising a reserve valve which is manually movable to a &#39;&#39;&#39;&#39;reserve&#39;&#39;&#39;&#39; position permitting the diver to use all of his reserve air, a torsion spring which constantly biases the reserve valve away from the &#39;&#39;&#39;&#39;reserve&#39;&#39;&#39;&#39; position to thereby prevent accidental usage of reserve air, and a spring-biased plunger responsive to pressure in the air tank and adapted to maintain the reserve valve in the &#39;&#39;&#39;&#39;reserve&#39;&#39;&#39;&#39; position when and only when the tank pressure is below a predetermined level. A spring-biased poppet moves back and forth in response to the breathing of the diver, and seats on a movable seat when the tank pressure is near the reserve level to thereby inform the diver that he should manually shift the reserve valve to &#39;&#39;&#39;&#39;reserve&#39;&#39;&#39;&#39; position. The movable poppet seat is maintained in operative position relative to the poppet during the entire dive, and is automatically shifted away from such operative position while the tank is filled, thus permitting the tank filling to occur in a fully automatic manner and regardless of the position of the reserve valve.

United States Patent 1 MacNiel 1 11 3,744,526 [451 July 10,1973

[ RESERVE AND FILL'VALVE FOR SELF-CONTAINED UNDERWATER BREATHING APPARATUS Douglas K. MacNiel, Costa Mesa, Calif.

[75] Inventor:

[52] US. Cl 137/5992, 128/1458, 141/18,

[51] Int. Cl A62b 9/02 [58] Field of Search 137/63 R, 599, 599.2,

[56] References Cited UNITED STATES PATENTS 2,954,792 10/1960 l-lagger 137/523 UX 3,147,761 911964 Lecocq 3,561,477 2/1971 Pinto 3,211,175' 10/1965' Replogle 141/18 X FORElGN PATENTS OR APPLICATIONS 1,030,137 3/1953 France 137/63 R l/1953 Italy 137/5992 ,mmm

Primary ExaminerRobert G. Nilson Attorney-Gausewitz, Carr & Rothenberg [5 7] ABSTRACT A fully-automatic reserve and fill valve for scuba gear, comprising a reserve valve which is manually movable to a reserve position permitting the 'diver to use all of his reserve air, a torsion spring which constantly biases the reserve valve away from the reserve position to thereby prevent accidental usage of reserve air, and a spring-biased plunger responsive to pressure in the air tank and adapted to maintain the reserve valve in the reserve position when and only when the tank pressure is below a predeterminedlevel. A spring-biased poppet moves back and forth in response to the breathing of the diver, and seats on a movable seat when the tank pressure is near the reserve level to thereby inform the diver that he should manually shift the reserve valve to reserve position. The movable poppet seat is maintained in operative position relative to the poppet during the entire dive, and is automatically shifted away from such operative position while the tank is filled, thus permitting the tank filling to occur in a fully automatic manner and regardless of the position of the reserve valve.

9 Claims, 11 Drawing Figures Jill PATENIEBJUHOW 3.744.526

MU b if 4 INVENTOR. 001/5445 A4 Mac/W54 RESERVE AND FILL VALVE FOR SELF-CONTAINED UNDERWATER BREATHING APPARATUS BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to the field of apparatus intended to ensure that a skin diver is informed of the fact that he only has a certain amount of air left in his air tank. Such certain amount" is caused to be sufficient to permit the diver to rise to the surface in a sufficiently slow manner to prevent the bends. Should the diver run completely out of air when he is submerged at a substantial depth, he would be in serious and possibly fatal trouble. The present invention also relates to the field of apparatus for filling the tanks of scuba gear in a simple and fool-proof manner by manipulating only one valve (other than the valving on the air-supply apparatus), and regardless of the position of the reserve valve. The present invention is particularly applicable to what is known as a J valve, and related valves wherein several tanks are employed, but various aspects of the invention are also applicable to valves which incorporate the first-state regulator (pressure reducer).

2. Description of Prior A Various types of reserve valves, J valves, etc., have been sold by the assignee of the present invention, and by various other companies, for many years. A major problem incident to such valves has been the prevention of accidental shifting of the control arm (crank) to such position that the reserve air is used up by the diver .without his being aware of the fact, so that he may become caught far below the surface with no air. In many valves of this type, only a slight shifting of the reserve crank, as by being caught on seaweed or accidentally jarred, would open the reserve valve a small amount and thereby permit escape of the reserve air unbeknownst to the diver.

A substantial improvement relative to reserve assemblies is described and'claimed in U.S. Pat. Application, Ser. -No. 8269, filed Feb. 3, 1970, now abandoned, for a Breathing Gas Regulator with a Safety Control, inventor John A. Fisher. Such patent application teaches a type of reserve valvewherein a greater amount of rotation is required in order to shift to the reserve position, with, consequent increase in the safety factor. However, even such invention does not protect against accidental rotations of, for example, 45 The invention described and claimed in the present patent application protects against any degree of accidental rotation, even a full 90 rotation to the reserve position, because upon release of the reserve valve it automatically springs back to the start dive" position, positively preventing exhausting of the reserve air. With the present invention, even an intentional manual shifting of the valve to the reserve position will not permit the air to be exhausted unless the diver intentionally and continuously holds such valve in the reserve" position, since the valve will not by itself remain in the reserve position unless the air pressure in the tank is reduced to the reserve level.

Relative to the tank-filling aspects of the present invention, it will be appreciated that a simple, fool-proof and automatic filling of the tank is greatly to be desired. With conventional J valves, etc., it is necessary to open the shut-off valve, and also shift the reserve valve to the reserve position, prior to filling of the tank. After the tank is filled, it is necessary to close the shutoff valve, and shift the reserve valve to its start dive" position (not reserve) before diving commences. Thus, it will be seen that it is possible for the user to accidentally forget to shift the reserve valve away from the reserve position prior to commencement of a dive, so that there will be no warning that the air is about to be exhausted. With the valve described and claimed in the present patent application, the person filling the tank need only open the shut-off valve prior to filling, and close the shut-off valve subsequent to filling. It doesnt make any difference whether the reserve valve is initially in the reserve position or not. Furthermore, and very importantly, the reserve valve will automatically assume the start dive position prior to the time the tank is filled, and will remain in such start dive posi tion at all times until the tank pressure is reduced to the reserve level. Thus, the present filling apparatus represents a very great increase in both convenience and safety.

It should be emphasized that it would be highly unsafe to provide a device which locks the reserve valve in its start dive position. This is because it is desired that the diver be able to instantly shift from the start dive mode to the reserve mode as soon as he senses that his air is being shut off, and without the necessity of going through any unlocking steps.

SUMMARY OF THE INVENTION The invention comprises means to bias the reserve valve in a direction away from the reserve position and into the normal or start dive position, in combination with means responsive to the pressure in the tank to hold the reserve valve in the reserve position after it has been manually shifted thereto, but only if the tank pressure has reduced to a predetermined reserve level. The invention further comprises a movable seat for the spring-biased poppet, in combination with stop means for the poppet and for the seat, the relationships being such that the seat is maintained in operative position at all times except during filling of the tank, whereupon the seat is shifted automatically away from the poppet in order to permit filling to occur independently of the position of the reserve valve. The above and other elements combine to produce the unitary result of permitting the tank to be filled through manipulation of only the shut-off valve as distinguished from the reserve valve, causing the reserve valve to be automatically in the start dive position after tank filling, and causing the reserve valve to remain in such start dive position at all times until the poppet and seat cooperate to apprise the diver of the fact that the air pressure is at the reserve level.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view showing the reserve and fill valve apparatus in its normal or start dive position, the valve being shown as mounted on an air tank;

FIG. 2 is a longitudinal sectional view of the reserve and fill valve apparatus;

FIG. 3 is a transverse sectional view taken on line 3-3 of FIG. 2;

FIG. 4 is an enlarged sectional view on line 4-4 of FIG. 2;

FIG. 5 is an isometric view showing the barrel portion of the reserve valve;

FIG. 6 is an isometric view of the piston or plunger adapted to lock the reserve valve in reserve position;

FIG. 7 is an enlarged sectional view corresponding generally to the central region of the showing of FIG. 2, illustrating the shut-off valve in open condition, and illustrating the positions of the movable seat and the poppet during filling of the air tank from an external source (and after the tank pressure has increased to a value above the reserve level);

FIG. 8 is a sectional view corresponding to FIG. 7, but showing the shut-off valve in closed condition;

FIG. 9 is a similar sectional view, showing the positions of the parts during purging of the air system of the scuba gear, such purging occurring by opening a purge valve associated wih the second stage regulator;

FIG. 10 is a similar sectional view, showing the positioning of parts after the pressure in the air tank has reduced to approximately the reserve level; and

FIG. 11 is a sectional view corresponding generally to FIG. 2, but showing the positions of the parts after the operator has manually shifted the reserve valve to reserve position, the valve then being held in its reserve position by the nose portion of the piston or plunger.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Throughout this specification and claims, the tank and associated passages are described as being filled with air. It is to be understood, however, that the word air is employed herein to comprehend any suitable breathing gas which will sustain the life and health of the skin diver.

Referring first to FIG. 1, the reserve and fill valve apparatus of the present invention is shown as mounted on the neck of a tank 10 adapted to contain air under high pressure. The reserve and fill valve is generally T- shaped, having an integral body 11 the stem portion 12 of which is threaded into the neck of tank 10 sufficiently far that a flange 13 will seat on the neck end and thereby compress a seal ring 14 (FIGS. 2 and 3). The body 11 has two arms 16 and 17 in axial alignment with each other and perpendicular to stem portion 12. In addition, the body has an upper boss portion 18 which extends upwardly in coaxial relationship to the stem 12.

Referring particularly to FIG. 2, the chamber within air tank 10 communicates through a tube 20 and passages 21 and 22 with a chamber 23 formed within arm 16 of body 11. The flow of air through such passages and chamber is controlled by three valves, one of which is a manually-operated shut-off valve 24 which is mounted at the outer end of arm 16.

Stated generally, shut-off valve 24 includes a handwheel 26 adapted when rotated to correspondingly rotate a rectangularly-sectioned tip element 27 (FIGS. 7-10) which operates in the manner of the tip of a screwdriver. Such tip 27 fits into a transverse groove 28 in a poppet 29 which is threadedly mounted in arm 16. An elastomeric sealing element 31 is seated in the inner end of poppet 29 and adapted to engage a valve seat 32.

Stated more definitely, the handwheel 26 is mounted on the square shank 33 of a stem 34, the inner end of the stem being flanged at 36 and provided with the previously indicated tip element 27. A bonnet 37 is threaded into a counterbore in arm 16 and into engagement with a washer 38. Such bonnet is axially bored and counterbored to receive, respectively, a cylindrical portion of stem 34, and .the flange 36 on such stem, there being an elastomeric gasket or washer 39 provided between flange 36 and the bottom of the recess in the bonnet.

The handwheel 26 is maintained on the square shank of stem 34, in non-rotatable relationship relative to such shank, by a helical compression spring 41 and a lock nut 42.

The shut-off valve 24 is, at all times during a dive and during tank filling, in the open position shown in FIGS. 7 and 9-11. When in such position, the poppet 29 is shifted to the left so that air may flow past the seal 31 and the seat 32 through a passage or port 43 to (or from) a cylindrical chamber 44 which is formed axially within the central portion of valve body 11 and also within arm 17 of such body. The flow of air through the cylindrical chamber 44, and through passage or port 43, etc., is controlled by two valves, the first being the reserve valve and the second being a spring-biased poppet or check valve which will be described in detail subsequently. The reserve valve comprises a barrel portion 46 which is most clearly illustrated in FIG. 5, and which is mounted in the chamber 44 for rotational but not axial movement. The inner end of barrel 46 comprises a hollow metal tube around which is rigidly mounted an elastomeric seal element having a land or closure portion 47 and an indented portion 48. Preferably, the land portion 47 comprises something less than 180, whereas the indented portion corresponds to the remainder of the circle or substantially more than 180.

A metal flange 49 is provided on barrel 46 adjacent elastomeric portions 47, 48, there being a continuous elastomeric land portion 50 between indented portion 48 and the flange. Therefore, the elastomeric material is continuous (and performs a scaling function) at all portions'adjacent the flange 49. Provided in spaced relationship from flange 49 is a cylindrical journal portion 51. Such portion 51, the flange 49, and the land portions 47 and 50 of the elastomeric means are in sliding contact with the cylindrical wall of chamber 44.

The portions 49 and 50 of barrel 46 divide the cylindrical chamber 44 into two portions each of which is adapted to serve as a conduit for air. The first such portion is designated 44a, and constitutes the inner end of the chamber 44. The second such portion is designated 44b, and constitutes the chamber portion between flange 49 and journal 51.

When the reserve valve is in the start dive position, the land 47 is uppermost as shown in FIGS. 2, 5, and 7-10. The elastomeric land 47 then blocks the flow of air through a passage 52 which is provided through the valve body 1 1 and which communicates with a cylindrical chamber 53 in boss portion 18. Thus, when the reserve valve is in the start dive position, air can only flow through chamber portion 44a by means of a spring-biased poppet and movable seat as described in detail hereinafter.

Upon rotation of the barrel 46 (and other portions of the reserve valve) through to the reserve position, shown in FIG. 11, the land 47 is shifted away from the lower end of passage 52 to thereby permit air to flow through such passage 52 to or from the chamber portion 44a. The spring-biased poppet and its movable seat are then shunted or bypassed.

Referring particularly to FIG. 5, the barrel 46 is integral with a cylindrical stem 54 which, in turn, is integral with a square shank 55 and a smaller diameter cylindrical shank end 56, the latter being threaded. The stem 54 passes rotatably through a bonnet 57 (FIGS. 2 and 11) which is threaded into the outer end of arm 17 of body 11, the inner end of the bonnet engaging a sealing washer 58. An O-ring 59 and backup ring 60 (FIG. 1]) ensure against leakage of air around the stem 54. Another O-ring seals the region between the outer end of arm 17 and the flange of bonnet 57.

Biasing Means for the Reserve Valve:

There will next be described the means for biasing the reserve valve, including the barrel portion 46 thereof, to the start dive position at which the passage 52 is blocked by the elastomeric land 47 as described above. Thus, flow through passage 52 is blocked, so that all flow through passages 21, 22 and chamber 23, port 43, etc., must be through the valve means (described hereinafter) comprising a poppet and a movable seat therefor.

The bias means for the reserve valve comprises a helical torsion spring 62 (FIGS. 2, 4 and 11) which is mounted coaxially around the outer end of arm 17 and around the bonnet 57, such bonnet having an external cylindrical surface which is generally flush with the external cylindrical surface of the outer end of the arm. The inner end 63 of spring 62 is bent radially-inwardly and is disposed in a groove 64 in arm 17. The outer end 66 of spring 62 is bent radially-outwardly and is disposed in a groove 67 which is formed in a hollow cylindrical cap or skirt 68.

Cap 68 has an end (outer) wall 69 the central portion of which is provided with a square opening to receive the square shank 55 of stem 54 in non-rotatable relationship. The cap 68 may rotate around the spring 62 and, in so rotating, turns the entire stem 54 and barrel 46 between the start dive and reserve positions.

The torsion spring 62 is so wound and so pre-biased that it is fully effective to maintain the reserve valve in the start dive position until the valve is locked in the reserve position as stated below. Furthermore, the spring is fully effective to return the reserve valve to the start 'dive position in the event that the valve is accidentally shifted away from such position.

A locknut 71 is threaded over the shank end 56, and a helical compression spring 72 is seated between such locknut and the cap end wall 69.

A crank or lever arm 74 is integrally formed on the cap 68, and has a hole 75 therein to receive the hooked end (FIG. 1) of an actuator rod 77. Rod 77 extends downwardly along the tank to a position where it may be conveniently pulled by the skin diver in order to pull the crank 74 down to the reserve" position, as soon as the diver becomes aware that his air supply is running low.

Stop means are provided to ensure that the barrel 46 of the reserve valve will be in the proper start dive" position when the crank 74 is in the upper position shown in various views other than FIG. 11, and also to ensure that the barrel will be in the proper reserve" position when the crank 74 is in the position of FIG. 11. The degree of rotation thus effected, when the rod 77 is pulled downwardly by the diver, is (in the present il- The spring 62 biases cap 68 clockwise (FIG. 4) until the lower end wall of groove 79 engages the pin 78, thereby preventing additional rotation and causing the reserve valve to remain in the start dive position. When the crank 74 is pulled downwardly, pin 78 is engaged by the other (upper) end wall of groove 79, this being the position which permits the locking mechanism described below to operate in the event that the pressure in the tank-has lowered to the reserve level. Of course, the torsion spring 62 is sufficiently weak that the diver can shift to reserve position without undue difficulty.

Pressure-Responsive Means for Locking the Reserve Valve in the Reserve Position The means for locking reserve valve barrel 46 in the reserve position (FIG. 11) when, and only when, the tank pressure has lowered to the reserve level, and after the diver has pulled on rod 77 to thus actuate crank 74 downwardly, comprises a piston or plunger 81 which is slidably mounted in the cylindrical chamber 53 in boss 18. Piston 81 (FIG. 6) has a downwardly-extending nose 82 which is adapted, when the piston is in the position shown in FIG. 11, to extend through an oversize opening 83 provided in the bottom wall of chamber 53. The nose 82 thus penetrates into the chamber portion 44b and into a port 84 which is formed in barrel 46 between journal 51 and flange 49. Port 84 is so located so as to be registered with the opening 83 when barrel 46 is in the reverse" position.

In addition to port 84, barrel 46 is formed with two other ports, numbered 85 and 86 (FIG. 3), which are adapted to conduct air into a chamber (described below) formed within the barrel.

The lower end of nose 82 is rounded to facilitate penetration into port 84, to lock the barrel in the reserve position. Alternatively, the relationships may be such that the barrel 46 is not positively locked in position, but instead is maintained in such position by detent action (the port 84 then being replaced by a dimple adapted to receive the nose end, and so shaped that the nose may be cammed out of the dimple in response to sufficient pressure on crank 74).

As best shown in FIG. 6, the piston 81 has grooves 87, at diametrically-opposite portions thereof, to permit air to flow past the piston at all times. The piston has an upwardly-extending shank or stem portion 88 which is cylindrical and which extends slidably into a corresponding cylindrical passage in a verticallyadjustable bonnet 89. Such cylindrical passage with the bonnet communicates axially with a hexagonallysectioned passage 90 which permits ambient pressure to act on the upper end of stem 88. Such ambient pressure is, of course, no more than that of the water at the depth at which the diver is swimming.

The bonnet 89 has a radial flange at the upper end thereof and in which is mounted an O-ring 91. In addition, an O-ring 92 and backup ring 93 are provided around stem 88 (FIG. 11) to prevent leakage around such stem.

The bonnet 89 is threaded into the outer end of boss 18 in such manner that the flange at the upper end of the bonnet enters a counter-bore in the boss. The position of the bonnet may be adjusted outwardly or inwardly by merely inserting a wrench in the hexagonal opening 90, and then turning the wrench in the appropriate direction. This effects adjustment of the bias of a helical compression spring 94 which is provided around stem 88 and is seated between piston 81 and a washer 95 at the under surface of bonnet 89.

It is important that the characteristics of spring 94, and the setting of bonnet 89, be so correlated to the diameter of stem or shank 88 that the spring will force the piston downwardly to the position shown in FIG. 10 (at which nose 82 seats on barrel 46) when the pressure in the tank 10 reduces to approximately the reserve level. Such reserve level is typically about 300 p.s.i., but other levels may be selected. Not only is the nose 82 then seated on the barrel 46, but the pressure relationships are caused to be such that the spring 94 then tends to force the piston 81 downwardly. It follows that as soon as the diver pulls on rod 77 (FIG. 1) the nose 82 will penetrate port 84 and thus maintain the barrel 46 in reserve position despite the continuing bias exerted by torsion spring 62.

It is pointed out that the upper radial surface 97 (FIGS. 6 and 11) of stem 88 forms one wall of a chamber within bonnet 89, and that water enters such chamber through the hexagonal port 90. Thus, the pressure of the water cooperates with the pressure of the spring 94 to tend to force piston or plunger 81 downwardly. These forces are opposed by the pressure of the air within tank 10 and which acts on the lower surfaces of piston 81 and nose 82. When the pressure in tank 10 is substantially above 300 pounds, the tank pressure is sufficiently great to counterbalance the pressure of spring 94 and the pressure of the water to thereby maintain the piston 81 in an upper position. The upper end 97 of stem 88 then seats against the upper wall of bonnet 89, it being noted that the hexagonal shape of opening 90 prevents the stem 88 from passing therethrough.

The water pressure does not vary greatly in comparison to tank pressure, so that the primary forces involved are those of the spring 94 and of the tank air, the hexagonal opening 90 serving as a way of permitting these forces to interact. Thus, the operation of the present apparatus does not vary excessively throughout the depths at which a skin diver normally swims.

The chamber 53 in boss 18 is caused to communicate, when the scuba gear is in operative condition, with a first stage regulator and thus with a second stage regulator the outlet of which connects to the mouthpiece through which the diver breathes. The connection to the first stage regulator is through a port 98 (FIGS. 1 and 3) which communicates with the chamber 53, there being a suitable O-ring 99 provided in an annular groove in order to effect a seal around the port 98 when the first stage regulator is mounted over the boss 18. Such mounting is conventionally effected by means of a yoke on the first stage regulator, and also by means of a handwheel which causes the end of a threaded shaft to penetrate a dimple 100 (FIG. 3) on the boss 18.

When the apparatus is not in use, but, instead, the

tank 10 is being filled, the first stage regulator is removed and the port 98 is connected to the filling apparatus. Air then enters through the port 98, passes through the associated valves and passages and then fills the tank as described below. In order to ensure that the tank will not be filled to an excessive pressure, a conventional safety device is provided as shown in FIG. 3 and comprises a rupturable disc 101 adapted to rupture and thus vent the tank in the event the tank pressure exceeds a predetermined amount. Vent means 102 are associated with the disc. The disc 101 is disposed in a passage 103 which communicates with passage 21.

Referring to FIG. 1, there is schematically represented in block form, at 104, either the filling apparatus or what may be termed the breathing apparatus (namely, the first stage and second stage regulators and the associated mouthpiece). During filling of the tank 10, the filling apparatus is associated with the presently described device by being caused to communicate with the port 98. During operation of the apparatus for diving, the first stage regulator is associated with the present device by being associated with the port 98.

The Breathing and Fill Valve, Comprising the Movable Valve Seat and and Associated Poppet and Stop Means In the above-cited co-pending US. Pat. application, Ser. No. 8269, there is described a spring-biased poppet valve (FIG. 3 of such patent application) which cooperates with a fixed seat, and which moves back and forth in response to the breathing of the diver and in response to the pressure in the associated tank. There will next be described the mechanism of the present invention, which incorporates not only a movable poppet but also a movable seat, together with stop means and seat-moving means permitting filling of the tank 10 of the present application automatically and without regard to the position of the reserve valve. The present valve may be termed a breathing and fill valve means.

Referring particularly to FIGS. 8-11, the barrel 46 is bored at the inner end thereof to provide a cylindrical chamber 106. Such chamber communicates coaxially with a slightly smaller-diameter chamber, the wall of which is internally threaded to receive an externallythreaded stop ring or retainer 107. The latter chamber merges with a slightly smaller-diameter cylindrical chamber 108.

The poppet is mounted slidably in the chamber 108, and also in the internally-threaded chamber adjacent thereto. Such poppet has a stem portion 109, a flange 111 in sliding engagement with the wall of chamber 108, and a poppet body 112 the inner end of which is generally hemispherical. The poppet body slides in the stop ring 107 in response to pressure changes, and also in response to the bias of a helical compression spring 113 which is seated around stem 109 betweenflange 111 and the closed end of chamber 108.

The movable valve seat is numbered 115, and comprises a hollow cylinder the external cylindrical wall of which is in sliding contact with the cylindrical wall of chamber 106. The passage 116 through seat is encompassed at the inner end of the seat by a generally frustoconical protuberance on which the hemispherical end of poppet body 112 is adapted to seat. An O-ring 117 is provided in the seat 115 to prevent leakage therearound.

Stop means are provided for both the poppet and for its seat 10. Thus, the poppet body 112 may only move inwardly (to the left in drawings) until flange 111 seats on the outer end of ring 107, despite the continued bias of spring 113. Correspondingly, the seat 115 may only move to the right until the shoulder at the necked-down region of the barrel (where chamber 106 meets the internally-threaded chamber) is engaged. The seat 115 may only move to the left until the inner end of chamber 44 is engaged, whereas the poppet may only move to the right (outwardly) until the stem 109 engages the closed end of chamber 108.

The spring 113 is carefully selected and correlated to the spring 94, and other factors, in such manner that the poppet body ,112 will be close to seat 115, despite the fact that the diver is inhaling, when the pressure in tank has reduced to almost the reserve level (such as 300 p.s.i.). By that time, and as above-stated, the spring 94 will have forced piston 81 downwardly into pressure engagement with the barrel 46 as shown in FIG. 10, so that the nose 82.may lock the barrel 46 in the reserve position as described relative to FIG. 11.

A helical compression spring may be provided in the inner (left) end of chamber 106, and seated between movable seat 115 and the inner (left) end wall of chamber 44. Such spring is adapted to maintain seat 115 in its right-most position (FIGS. 2 and 9-11) at all times except during filling of tank 10, and despite the effects of aging, corrosion, etc., on the slidability of seat 115. Such spring is adapted to permit leftward shifting of seat 115 substantially to the positions of FIGS. 7 and 8.

The operation of the poppet body 112, seat 115, etc. will be described under the following sub-heading, in conjunction with the description of the operation of present reserve and fill valve apparatus.

OPERATION There will first be described the operation of present apparatus during filling of tank 10, following which there will be described the operation during use in diving.

Frequently, the tank 10 is not filled until the pressure therein has reduced to a lower value than the reserve level, less than 300 p.s.i. in the example. Accordingly, when the tank is filled, the crank 74 is initially in the reserve position which is shown in FIG. 11, the spring 94 then pressing piston 81 downwardly until nose 82 is in locking position in port 84.

A suitable high-pressure filling apparatus (air pump, pressure tank, etc.) is then associated with the boss 18 and in communication with port 98 (FIGS. 1 and 3). The operator effecting filling of tank 10 then merely makes sure that the shut-off valve 24 is in open position, it being unnecessary for the operator to pay any attention to the reserve valve.

The operator then starts the inflow of air from the fill apparatus through port 98 into chamber 53, thence through passage 52 to chamber portion 44a (FIG. 11), thence through passage 43 and chamber 23 to passages 22 and 21, and through tube 20 into the tank 10. The pressure in the tank 10 thus builds up to a value somewhat above the reserve level, namely somewhat above 300 p.s.i. in the present illustration, thus causing pres sure to bear on the piston 81 to force the same upwardly against the bias of spring 94 and due to the fact that surface 97 at the upper end of stem 88 is exposed (through port 90) to the atmosphere. As soon as the piston 81 moves upwardly sufficiently far that the nose 82 is no longer in port 84, the barrel 46 is no longer locked against rotation. Accordingly, the torsion spring 62 operates to pivot the barrel 46 in a clockwise direction (as viewed in FIG. 3 and FIG. 4) until the crank 74 assumes the position shown in such figures, stop pin 78 then being engaged by the lower end of arcuate groove 79.

The barrel 46 being thus shifted to the start dive position, the elastomeric land 47 is in blocking position over the lower end of passage 52, thereby blocking the flow of air through the above-described flow path. Air

from the fill source then passes downwardly through port 83 and into chamber portion 44b, as shown in FIG. 7. From such chamber portion, the air passes inwardly through the three ports 84-86 and into the chamber containing the inner end of poppet body 112 and the adjacent valve-seat end of valve seat 115. Due to the pressure and drag forces created by the inflowing highpressure air, the valve seat is thereupon airpressure actuated to the left from the position shown in FIG. 11 to the position shown in FIG. 7. The left end of seat 115 then engages the left-end wall of chamber portion 44a, and spring 113 is operative to shift the poppet 112 to the left until flange 111 seats on ring 107.

As shown in FIG. 7, the amount of leftward travel of the valve seat 115 is substantially greater than the amount of leftward travel of the poppet body 112, so that the seat separates from the poppet and creates a flow path through passage 116 to port 43 and communicating passages and chambers and thence into the tank.

The filling operation then continues through the described flow path until the tank is filled to the desired pressure. It is emphasized that after the tank is thus filled, the reserve valve is automatically in the start dive position without the necessity of relying upon any operator to ensure that such is the case.

In those situations when the tank is filled while the reserve valve is already in the start dive position (tank pressure above 300 p.s.i.), the operation is the same as that described above relative to the last portion of the filling procedure. Thus, it is immaterial whether the reserve valve is initially in the reserve position or the start dive position.

After the tank is thus filled, the operator closes the shut-off valve 24 to the closed position of FIG. 8, and removes the boss 18 from the'filling apparatus. He then connects to boss 18 the first-stage regulator and associated gear as stated above. He is then ready to make a dive as soon as he opens the shut-off valve 24, it being again unnecessary to operate the reserve valve since it is automatically in start dive position.

Normally, the first thing the diver does upon initiation of a dive is to purge the lines, this being accomplished by opening a purge valve associated with the second-stage regulator. This causes a substantial rightward flow of air (FIG. 9) through passage 43 and passage 116. The pressure and dynamic forces thus resulting cause the movable seat 115 to shift to the right to the position shown in FIG. 9. During part of this rightward-shifting movement, the seat 115 operates to shift the poppet body 112 part of the way to the right. Thereafter, the fluid forces pressing on the poppet body 112 shift the same the remainder of the distance to the right, and permit flow of air through ports 84-86, chamber portion 44b, port 83, chamber 53, and grooves 87 to port 98 leading to the first-stage regulator. Thus, the movable seat 115 is air-pressure shifted to its fully operative position as shown in FIG. 9. As stated above, a helical compression spring may be provided to aid in such shifting.

As soon as the purge operation is terminated, the spring 113 becomes operative to shift the poppet body 112 leftward into seated position on seat 115. It is pointed out that spring 1 13 is not operative to shift the seat 115 leftward away from the stop means therefor, since the pressure in chamber 106 maintains the seat 115 in its rightward-shifted position (FIG. despite the spring force.

Even in the event that the diver does not effect any purge operation, the first full inhalation taken by the diver will cause the seat 115 to shift rightward as described.

Upon each inhalation effected by the diver, the pressure in chamber 53 and associated ports and chambers is reduced. Since there is no seal around flange 11 l, the pressure in chamber 108 is likewise reduced. Such pressure reduction in chamber 108 is sufficient to cause the poppet to shift to the right, despite the bias of spring 113, and thereby permit flow of air thorugh passage 1 16 to chamber 53 and thence to the regulator. When the diver exhales, the spring 113 pushes the poppet back to the left. Thus, the poppet 112 moves back and forth, and the degree of rightward movement (during inhalation) depends upon the pressure in tank 10, since such pressure determines the upstream force which tends to shift poppet 112 to the right.

Because the spring 113 is so selected that the poppet will only open a small amount (for example, the amount shown in FIG. 10) when the pressure in tank 10 reduces to substantially the reserve level, such as 300 p.s.i., the diver is forced to notice that he is not receiving sufficient air. This will not occur, however, until (as described above) the spring 94 has pushed the piston 81 downwardly to the position shown in FIG. 10, at which the nose 82 is ready to snap into port 84.

The operator then shifts to the reserve" position by merely grasping the lower end of rod 77 (FIG. 1) and thus pulling crank 74 downwardly through the 90 rotation permitted by the arcuate groove 79 (FIG. 4) associated with stop pin 78. At the conclusion of the 90 rotation, the port 84 becomes registered with nose 82 whereupon the spring 94 forces the nose into the port as shown in FIG. 11, thus locking the barrel 46 in the reserve position at which land 47 is no longer in blocking relationship to passage 52.

It follows that the diver will receive air from chamber 23 through passage 43 into chamber portion 44a,

thence through passage 52, chamber 53 and the associated regulator apparatus. He then knows that he must make his ascent in order to be at the surface by the time his air is completely exhausted.

If, prior to the time the air in tank 10 is near the reserve level, the crank 74 is accidentally shifted (as by seaweed or by contact with any object) part or all of the way to the reserve position, it will not remain in such reserve position but will instead snap back due to the action of the torsion spring 62. Thus, the present invention minimizes the possibility that the reserve air will be exhausted without the diver being cognizant of the fact.

The piston 81 is in an upwardly-shifted position not only when shut-off valve 24 is open and the tank pressure is above the reserve level, but also when valve 24 is closed and sufficient air has not yet been vented from the chamber 53, etc.

The foregoing detailed description is to be clearly understood as given by way of illustration and example only, the spirit and scope of this invention being limited solely by the appended claims.

I claim:

1. A reserve valve apparatus for scuba gear, which comprises:

a valve body having a valve chamber therein,

a valve seat provided in said body and exposed to said chamber,

a poppet movably mounted in said chamber for cooperation with said valve seat,

a spring to bias siad poppet toward said seat,

first passage means to conduct air from the air tank means of the scuba gear to said seat for flow through said seat into said chamber under the control of said poppet,

second passage means to conduct air from said cham her to the pressure regulator means of the scuba gear and thence to the diver,

third passage 'means to conduct air from said first passage means to said second passage means independently of said seat and despite seating of said poppet on said seat,

a reserve control element rotatably mounted on said valve body, reserve valve means rotatably mounted in said valve body and responsive to the rotated position of said reserve control element, said reserve valve means being adapted to permit flow of air through said third passage means when said reserve control element and said valve means are in one rotated position, thereby effecting passage of reserve air from said tank means to the diver despite reduction of the air pressure in said tank means to a level below a predetermined reserve level which is insufficiently high to effect air-pressure forcing of said poppet a substantial distance off said seat, said reserve valve means being operative, when said reserve control element and said valve means are in another rotated position, to block flow of air through said third passage means whereby all air flow to the diver is through said seat under control of said poppet and said spring means,

a torsion spring operably connected to said reserve control element and to' said reserve valve means to effect rotation thereof to said other rotated position, said torsion spring being sufficiently strong torotate said reserve control element and said reserve valve means to said other rotated positions despite accidental shifting thereof toward said one rotated position, and being sufiiciently weak to permit the diver to rotate said reserve control el- I ement manually to said one rotated position, and

means responsive to the air pressure in said tank means to maintain said reserve control element and said reserve valve means at said one rotated position, after manual shifting thereto by the diver, when, and only when, the air pressure in saidtank means is at or below a predetermined reserve level.

2. The invention as claimed in claim 1, in which said reserve valve means is directly connected to said re serve control element for rotation therewith, in which said means to maintain said reserve control element in said one rotated position includes a cylinder formed in said valve body radially of said valve means, and a piston mounted in said cylinder for movement toward and away from said valve means, in which spring means are provided to bias said piston toward said reserve valve means, in which means are provided to cause the pressure of the air from said tank means to act upon said piston to thereby force the same away from said reserve valve means when the tank air pressure is sufficiently above said predetermined reserve level, and in which means are provided on said piston and on said reserve valve means to maintain said reserve valve means in said one rotated position when the air pressure in said tank means is below said predetermined reserve level.

3. The invention as claimed in claim 2, in which said cylinder forms part of said second passage means, in which means are provided to permit air flow around said piston, and in which means are provided to effect application of the ambient water pressure to a portion of said piston.

4. The invention as claimed in claim 2, in which said spring means for said piston is correlated to said spring for said poppet in such manner that said piston will be sufficiently close to said valve means to effect maintenance of said reserve valve means in said one rotated position when the air pressure in said tank means is sufficiently low that said poppet will shift only a slight distance off said seat therefor in response to an inhalation by the diver.

5. The invention as claimed in claim 1, in which said seat is movably mounted in said valve body for movement toward and away from said poppet, in which stop means are provided to limit the extent of movement of said seat toward said poppet, and in which stop means are provided to limit the extent of movement of said poppet toward said seat, said stop means being so related to each other that said seat may move away from said poppet a substantial distance when said poppet is seated on said stop means therefor, whereby to permit filling of said tank means through said second passage means and through said seat to said firs passage means, regardless of the position of said reserve control element and said reserve valve means.

6. The invention as claimed in claim 5, in which said reserve valve means includes a barrel, in which said pressure responsive means comprises a piston slidably mounted in said valve body for movement radially of said barrel toward and away therefrom, said piston including a locking portion, said piston being exposed to air pressure from said tank means whereby the pressure on said piston reduces as the air pressure in said tank means reduces, the manner of exposure of said piston to said air pressure from said tank means being such that said tank air pressure tends to force said piston away from said barrel, a portion of said piston being exposed to the pressure of the ambient water whereby to provide a pressure differential across said piston, spring means to bias said piston toward said barrel with a 7 force sufficiently great that said locking portion of said piston will be engaged with said barrel when the air pressure in said tank means has reduced to a value near said predetermined reserve level, and in which means are provided on said barrel to receive said locking portion of said piston when said reserve control element and thus said barrel have been manually rotated by the diver to said one position and when said tank pressure is near said predetermined reserve level.

7. The invention as claimed in claim 1, in which a shut-off valve is provided to block the flow of air through said valve body, such shut-off valve being manually operable by the diver.

8. The invention as claimed in claim 1, in which said reserve valve means includes a barrel, in which said torsion spring is mounted around an arm portion of said valve body, in which a hollow cap is rotatably mounted around said arm portion and around said torsion spring, in which one end of said torsion spring is mounted in said arm in such manner that said one end will not shift circumferentially relative to said arm, in which the other end of said torsion spring is mounted in said cap in such manner that said other spring end will not shift circumferentially relative to said cap, in which a crank is provided to effect rotation of said cap by the diver, said crank being said reserve control element, in which said crank and cap are connected to said barrel whereby rotation of said crank and cap will effect corresponding rotation of saidbarrel, and in which stop means are provided to limit the degree of rotation of said cap and thus of said barrel.

9. An automatic reserve and fill valve for scuba gear,

which comprises:

' a valve body,

a barrel rotatably mounted in said valve body,

said barrel having a chamber therein,

a valve seat slidably mounted in said barrel chamber for movement generally axially of said barrel,

a poppet movably mounted in said barrel chamber for movement generally axially of said barrel toward and away from said valve seat,

a spring to bias said poppet toward said valve seat for substantial seating thereon,

first passage means to conduct air from said barrel chamber, at the region adjacent the junction between said valve seat and poppet, toward the pressure-reducing regulator means and mouthpiece of 'the scube gear when the same is being employed during a dive,

second passage means to conduct, during a dive, air

from the tank means of said scuba gear to the passage through said valve seat, whereby air may flow to said valve seat from said second passage means and thence through said valve seat to said first passage means when said poppet is not in seated condition on said seat, third passage means to conduct air between said first passage means and said second passage means independently of said valve seat and said poppet, said third passage means having a portion adjacent said barrel, said barrel having seal means thereon to prevent flow through said third passage means when said barrel is in a first predetermined rotated position referred to as the start dive position, said barrel permitting air flow through said third passage means when said barrel is in a second predetermined rotated position at which said passage means is not blocked and which is referred to as the reserve position,

a torsion spring operably connected to said barrel to bias the same rotationally toward said start dive position, said torsion spring being sufficiently strong to rotate said barrel back to said start dive position in the event said barrel is accidentally rotated away from such position, said torsion spring being sufficiently weak to permit said barrel to be manually rotated to said reserve position by the diver, and

means responsive to the pressure of the air in said tank means and operative, after said barrel has been manually rotated from said start dive position to said reserve position, to maintain said barrel in said reserve position despite the bias of said torsion spring and when the air pressure in said maintain said barrel in said reserve" position tank means has reduced to a predetermined rewhen the air pressure in said tank means is above serve level, said predetermined reserve level. said pressure-responsive means being inoperative to 

1. A reserve valve apparatus for scuba gear, which comprises: a valve body having a valve chamber therein, a valve seat provided in said body and exposed to said chamber, a poppet movably mounted in said chamber for cooperation with said valve seat, a spring to bias siad poppet toward said seat, first passage means to conduct air from the air tank means of the scuba gear to said seat for flow through said seat into said chamber under the control of said poppet, second passage means to conduct air from said chamber to the pressure regulator means of the scuba gear and thence to the diver, third passage means to conduct air from said first passage means to said second passage means independently of said seat and despite seating of said poppet on said seat, a reserve control element rotatably mounted on said valve body, reserve valve means rotatably mounted in said valve body and responsive to the rotated position of said reserve control element, said reserve valve means being adapted to permit flow of air through said third passage means when said reserve control element and said valve means are in one rotated position, thereby effecting passage of reserve air from said tank means to the diver despite reduction of the air pressure in said tank means to a level below a predetermined reserve level which is insufficiently high to effect air-pressure forcing of said poppet a substantial distance off said seat, said reserve valve means being operative, when said reserve control element and said valve means are in another rotated position, to block flow of air through said third passage means whereby all air flow to the diver is through said seat under control of said poppet and said spring means, a torsion spring operably connected to said reserve control element and to said reserve valve means to effect rotation thereof to said other rotated position, said torsion spring being sufficiently strong to rotate said reserve control element and said reserve valve means to said other rotated positions despite accidental shifting thereof toward said one rotated position, and being sufficiently weak to permit the diver to rotate said reserve control element manually to said one rotated position, and means responsive to the air pressure in said tank means to maintain said reserve control element and said reserve valve means at said one rotated position, after manual shifting thereto by the diver, when, and only when, the air pressure in said tank means is at or below a predetermined reserve level.
 2. The invention as claimed in claim 1, in which said reserve valve means is directly connected to said reserve control element for rotation therewith, in which said means to maintain said reserve control element in said one rotated position includes a cylinder formed in said valve body radially of said valve means, and a piston mounted in said cylinder for movement toward and away from said valve means, in which spring means are provided to bias said piston toward said reserve valve means, in which means are provided to cause the pressure of the air from said tank means to act upon said piston to thereby force the same away from said reserve valve means when the tank air pressure is sufficiently above said predetermined reserve level, and in which means are provided on said piston and on said reserve valve means to maintain said reserve valve means in said one rotated position when the air pressure in said tank means is below said predetermined reserve level.
 3. The invention as claimed in claim 2, in which said cylinder forms part of said second passage means, in which means are provided to permit air flow around said piston, and in which means are provided to effect application of the ambient water pressure to a portion of said piston.
 4. The invention as claimed in claim 2, in which Said spring means for said piston is correlated to said spring for said poppet in such manner that said piston will be sufficiently close to said valve means to effect maintenance of said reserve valve means in said one rotated position when the air pressure in said tank means is sufficiently low that said poppet will shift only a slight distance off said seat therefor in response to an inhalation by the diver.
 5. The invention as claimed in claim 1, in which said seat is movably mounted in said valve body for movement toward and away from said poppet, in which stop means are provided to limit the extent of movement of said seat toward said poppet, and in which stop means are provided to limit the extent of movement of said poppet toward said seat, said stop means being so related to each other that said seat may move away from said poppet a substantial distance when said poppet is seated on said stop means therefor, whereby to permit filling of said tank means through said second passage means and through said seat to said first passage means, regardless of the position of said reserve control element and said reserve valve means.
 6. The invention as claimed in claim 5, in which said reserve valve means includes a barrel, in which said pressure responsive means comprises a piston slidably mounted in said valve body for movement radially of said barrel toward and away therefrom, said piston including a locking portion, said piston being exposed to air pressure from said tank means whereby the pressure on said piston reduces as the air pressure in said tank means reduces, the manner of exposure of said piston to said air pressure from said tank means being such that said tank air pressure tends to force said piston away from said barrel, a portion of said piston being exposed to the pressure of the ambient water whereby to provide a pressure differential across said piston, spring means to bias said piston toward said barrel with a force sufficiently great that said locking portion of said piston will be engaged with said barrel when the air pressure in said tank means has reduced to a value near said predetermined reserve level, and in which means are provided on said barrel to receive said locking portion of said piston when said reserve control element and thus said barrel have been manually rotated by the diver to said one position and when said tank pressure is near said predetermined reserve level.
 7. The invention as claimed in claim 1, in which a shut-off valve is provided to block the flow of air through said valve body, such shut-off valve being manually operable by the diver.
 8. The invention as claimed in claim 1, in which said reserve valve means includes a barrel, in which said torsion spring is mounted around an arm portion of said valve body, in which a hollow cap is rotatably mounted around said arm portion and around said torsion spring, in which one end of said torsion spring is mounted in said arm in such manner that said one end will not shift circumferentially relative to said arm, in which the other end of said torsion spring is mounted in said cap in such manner that said other spring end will not shift circumferentially relative to said cap, in which a crank is provided to effect rotation of said cap by the diver, said crank being said reserve control element, in which said crank and cap are connected to said barrel whereby rotation of said crank and cap will effect corresponding rotation of said barrel, and in which stop means are provided to limit the degree of rotation of said cap and thus of said barrel.
 9. An automatic reserve and fill valve for scuba gear, which comprises: a valve body, a barrel rotatably mounted in said valve body, said barrel having a chamber therein, a valve seat slidably mounted in said barrel chamber for movement generally axially of said barrel, a poppet movably mounted in said barrel chamber for movement generally axially of said barrel toward and away from said valve seat, a sPring to bias said poppet toward said valve seat for substantial seating thereon, first passage means to conduct air from said barrel chamber, at the region adjacent the junction between said valve seat and poppet, toward the pressure-reducing regulator means and mouthpiece of the scuba gear when the same is being employed during a dive, second passage means to conduct, during a dive, air from the tank means of said scuba gear to the passage through said valve seat, whereby air may flow to said valve seat from said second passage means and thence through said valve seat to said first passage means when said poppet is not in seated condition on said seat, third passage means to conduct air between said first passage means and said second passage means independently of said valve seat and said poppet, said third passage means having a portion adjacent said barrel, said barrel having seal means thereon to prevent flow through said third passage means when said barrel is in a first predetermined rotated position referred to as the ''''start dive'''' position, said barrel permitting air flow through said third passage means when said barrel is in a second predetermined rotated position at which said passage means is not blocked and which is referred to as the ''''reserve'''' position, a torsion spring operably connected to said barrel to bias the same rotationally toward said ''''start dive'''' position, said torsion spring being sufficiently strong to rotate said barrel back to said ''''start dive'''' position in the event said barrel is accidentally rotated away from such position, said torsion spring being sufficiently weak to permit said barrel to be manually rotated to said ''''reserve'''' position by the diver, and means responsive to the pressure of the air in said tank means and operative, after said barrel has been manually rotated from said ''''start dive'''' position to said ''''reserve'''' position, to maintain said barrel in said ''''reserve'''' position despite the bias of said torsion spring and when the air pressure in said tank means has reduced to a predetermined reserve level, said pressure-responsive means being inoperative to maintain said barrel in said ''''reserve'''' position when the air pressure in said tank means is above said predetermined reserve level. 